Ok heres some back story i bought this 01 xj 3 weeks ago. It had codes when i purchased it. p0456 p0306 p0301
Small evap leak cylinder 1 and 6 mis fire. It drove fine untill you would stop and let rpms fall to idle. Never missed at idle at start up and the only thing i would do to stop it is to put her in neutral and turn it off and back on and the miss would stop untill the next red light at least.

First thing i did was change the gas cap and it has fixed the p0456.
i installed brand new sparkplugs with no changes to mis
i check the injectors all click well and pulled up good on the multimeter.
i checked fuel pressure witch is in spec.
After all that i changed out tps still no change to misfire at idle after driving and coming to a stop
I changed out the cps still no change
I checked tps with multimeter good
I checked wires to tps perfect voltage and no spike when moving throttle or tapping on tps

I did mess up the trottle control cable adjustment im guessing when i was changing checking plugs i reset the adjustment and now it shifts slightly harded then before mainly 2 gear.

Im stumped what could i be missing what should i check?

I rebooted the pcu now when i put it in neutral it revs up but thats the only change ive seen so far lol

Now im pulling up p0121 p0300 p0306

 

What kind of spark plugs did you use?.. The 00 and 01 seem to run best with NGK ZFR5N.. My 2000 would run rough and crappy and a mis once and while,,The Jeep didnt seem to like anything but the NGK..
I think it has has to do with how the NGKs handle the waste spark system that the 00 and 01 have..

My 2000 also will run ok with the OEM suggested S-plug --- Champion RC12ECC ..But a little better with the NGK..

All the rest of the plug like E3 or other fancy plugs didnt seem to do very well.

 

Im runnig bosch iridum plugs ill try the ngks

 

Is the airbag light on?

 

No air bar light

 

No air bar light

 

Did you remove the iridium plugs? They're well known to cause problems in our Jeeps. Start there and keep us posted.

 

Headed to oreilys now ill let yall know in a couple hours after a test drive im gunna compression test it also

 

Ngk's installed still no change

 

Installed new map sensor and shes running better pulled codes and im reading p0121 and p0700

 

P0121-TPS VOLTAGE DOESNOT AGREE WITH MAP
When Monitored: With the engine runningand no MAP sensor or TPS DTC’s set. Engine speed must be greater than 1600 RPM.
Set Condition: The PCM performs twoseparate tests. When the manifold vacuum is low, the TPS signal should be high.If the proper TPS voltage is not detected when the two conditions are met, aDTC will be set after 4 seconds.

POSSIBLE CAUSES

HIGH RESISTANCE IN 5VOLT SUPPLY CIRCUIT
HIGH RESISTANCE TOGROUND IN 5 VOLT SUPPLY CIRCUIT
INTERMITTENT CONDITION
HIGH RESISTANCE IN 5VOLT SUPPLY CIRCUIT
HIGH RESISTANCE TOGROUND IN 5 VOLT SUPPLY CIRCUIT


MAP SENSOR
HIGH RESISTANCE IN MAPSENSOR SIGNAL CIRCUIT
HIGH RESISTANCE TOGROUND IN MAP SENSOR SIGNAL CIRCUIT
HIGH RESISTANCE INSENSOR GROUND CIRCUIT


THROTTLE POSITIONSENSOR
HIGH RESISTANCE INTHROTTLE POSITION SENSOR SIGNAL CIRCUIT
HIGH RESISTANCE TOGROUND IN THROTTLE POSITION SENSOR SIGNAL CIRCUIT
HIGH RESISTANCE INSENSOR GROUND CIRCUIT
PCM
That new MAP sensor may be giving you the problem but the P0700 is indicating the PCM has detected a fault in the TCM diagnostics, which may be caused by a TPS fault (or the throttle valve adjustment issue may be causing the issue).


Check the 5 volt supply voltage to the TPS and ground circuit voltage
With the TPS connector removed, and the key to RUN, check the voltage at the pin cavity with the Orange wire. Should be 5.0 volts +/- 0.5 volts.
Check the voltage at the pin cavity with the Brown/Yellow tracer wire. Should be .015 to .020 volts.

 

I checked tps wires running and tps sensor with multimeter check out good could it just be my coil pack since it has a constant cylinder 1and 6 mis? I did a compression test today all check out good

 

High possibility of the coil rail being bad. Cylinders 1 and 6 are companion cylinder and are fired by #1 coil on the rail. But what about those DTC codes you mentioned? No coil DTC?

Here's a coil rail test if you want to look in to it some more.

 

Just pulled the rail i was goin to inpect wires and the connector has what looks like a full tube of dielectric grease gunna clean it out and reinstall the old rail before i put in the new one i just got 15 min ago

 

You can also try moving the injectors around to see if the misfire moves .